Currently, fan shrouds that are in a box shape are excitable (by resonance) in the operating range of the fan motor or other periodic signals in the machine the fan is placed in, such as a vehicle. In addition, due to the box-like structure of typical shrouds, there is a need for substantial structural re-enforcement to minimize warping and distortion. However, the use of such significant re-enforcement can increase the manufacturability (e.g. moldability) of the shroud and cost of materials, while adversely affecting airflow properties.
Thus, there is a need to provide an improved fan shroud structure that reduces resonance, and improves stiffness and manufacturability.